一、背景

BufferedImage是将图片整个加载到内存中的，而图片又比较大，可能有多个线程在转，所以会有内存溢出的问题。因而使用ImageMagick+Im4Java去裁剪图片

二、实现

1、获取图片的长和宽

public static void main(String[] args) throws Exception {Iterator<ImageReader> iterator = ImageIO.getImageReadersByFormatName("png");ImageReader reader = iterator.next();File file = new File("C:\\Users\\jie10.gao\\Pictures\\513698797896.png");FileInputStream in = new FileInputStream(file);ImageInputStream imageInputStream = ImageIO.createImageInputStream(in);reader.setInput(imageInputStream, true);int w, h;int width = reader.getWidth(0);int height = reader.getHeight(0);float fw = (float) width;float fh = (float) height;float number = fw / fh;if (number > (16.0 / 9)) {w = height * 16 / 9;h = height;} else {w = width;h = width * 9 / 16;}cutImage("C:\\Users\\jie10.gao\\Pictures\\513698797896.png", "D:\\newPicture.png", (width - w) / 2, (height - h) / 2, w, h);}

2、开始裁剪

//ImageMagick的安装路径
public static String imageMagicPath = "C:\\Program Files\\ImageMagick-7.1.0-Q16-HDRI";public static void cutImage(String imagePath, String newPath, int x, int y, int width, int height)throws Exception {IMOperation op = new IMOperation();op.addImage(imagePath);/** width：裁剪的宽度 * height：裁剪的高度 * x：裁剪的横坐标 * y：裁剪纵坐标 */op.crop(width, height, x, y);op.addImage(newPath);ConvertCmd convert = new ConvertCmd();convert.setSearchPath(imageMagicPath);convert.run(op);}